Multi-fuel system for internal combustion engines

ABSTRACT

In a multi-fuel system for diesel engines, natural gas is mixed with diesel fuel and conditioned in a mixing chamber before being injected into the mixing chamber of the engine. Filtered blow-by gas may also be introduced into the combustion chamber. A computerized controller is used to determine and control the proportion of diesel fuel, natural gas fuel, the mixing and conditioning of these fuels, and the supply of filtered blow-by gas.

RELATED APPLICATION

This application claims the benefit of U.S. Provisional Application No.61/840,129, filed on Jun. 27, 2013.

BACKGROUND OF THE INVENTION

The present invention generally relates to fuel systems for an internalcombustion engine. More particularly, the present invention relates to amulti-fuel system for an internal combustion engine that utilizes bothdiesel and natural gas.

It is estimated that there are currently three hundred million vehicleson America's roads. Every day, the average American spends almost anhour driving in a car. Additionally, approximately seventy percent ofgoods that are shipped in America travel on commercial vehicles.Clearly, automobiles are an integral part of everyday life in America.The same is true for most countries around the world. The world'sdependence on automobiles creates a similar dependence on fuel sourcesto power these automobiles. Most vehicles on the road today are fueledby gasoline or diesel fuel. Most commercial vehicles are fueled bydiesel fuel.

The reliance on fossil fuels creates a host of problems. Diesel fuelprices fluctuate on a daily basis, but there is a definite upward trendin fuel pricing. There are no indicators to suggest that these fuelprices will go down in the foreseeable future. The air pollutionproblems inherent in the operation of gasoline fueled and diesel oilfueled internal combustion engines are well known. These air pollutantsinclude carbon monoxide, nitrogen dioxide, particulate matter, ozone,sulfur dioxide and lead. All these pollutants are known sources of awide variety of health problems in humans, as well as ozone depletionand acid rain in the environment. Many speculate that air pollution iscausing the gradual and irreversible warming of the globe.

For these reasons, various emission control devices are presently inuse, and may be required by federal regulations in order to reduce theamount of pollutants discharged in the atmosphere by internal combustionengines. These emission control devices are in response to various AirQuality Standards set by the Environmental Protection Agency (EPA),including the Clean Air Act. Individual states also have their ownenvironmental protection regulations and methods of enforcement.California's Air Resources Board (CARB) is the strictest regulatory bodyconcerned with pollution in the country. The emissions standards set byCARB are stricter than the federal EPA requirements, specifically withregard to hydrocarbon and nitrogen oxide emissions, which become smog.Currently, sixteen other states have adopted, or are in the process ofadopting, California's strict emissions standards.

Emission control devices, however, only remove a portion of thepollutants and are subject to deterioration with the passage of time.Also, they often hinder engines from operating at peak efficiencies.Such emission control devices also are somewhat limited in their abilityto remove pollutants, and increase the costs of the automobilessignificantly.

Discharge or burning of blow-by gas also contributes to emissions. In adiesel powered engine, oil is used to lubricate the crankshaft andconnecting rod bearings. The crankcase is mainly filled with air andoil. It is the intake manifold that receives and mixes fuel and air fromseparate sources. The fuel/air mixture in the intake manifold is drawninto the combustion chamber where it is ignited by a sparkplug, or as aresult of compression in the combustion chamber due to the movement ofthe piston shaft. Although piston rings, disposed around the outerdiameter of the pistons within the piston cylinder, are intended to sealoff from the crankcase the unburned and burned fuel and air injectedinto the combustion chamber, the piston rings are unable to completelyseal off the piston cylinder. Thus, waste gas enters the crankcase,which is commonly called “blow-by” gas.

Blow-by gasses mainly consist of contaminants such as hydrocarbons(unburned fuel), carbon dioxide and/or water vapor, all of which areharmful to the engine crankcase. The trapping of blow-by gasses in thecrankcase allows the contaminants to condense and accumulate over timein the engine crankcase. Condensed contaminants form corrosive acids andsludge in the interior of the crankcase. This decreases the ability ofthe engine oil in the crankcase to lubricate the cylinder andcrankshaft. The degraded oil that fails to properly lubricate thecrankshaft components can be a factor in increased wear and tear in theengine, as well as poor engine performance.

Crankcase ventilation systems have been developed to expel blow-bygasses out of a positive crankcase ventilation (PCV) valve and into theintake manifold to be re-burned. However, such blow-by gasses removedfrom the crankcase often contain relatively high levels of lubricatingoil and the like, which are introduced into the air intake manifold andthus into the combustion chamber, which increases the pollutiongenerated by the vehicle.

These issues are especially problematic in diesel engines as dieselengines burn diesel fuel which is much more oily and heavy thangasoline. Thus, the blow-by gas produced by the crankcase of the dieselengine is much more oily and heavy than gasoline blow-by gas. Of course,the burning of such diesel blow-by gas creates even a greater pollutionconcern.

Recently, there have been found vast sources of natural gas within theUnited States. Natural gas is also sometimes used as a fuel for internalcombustion engines. It has the capability of producing less combustionpollutants and decreasing engine operating costs without complexemission control devices. Its use is anticipated to reduce the rate ofworld fossil fuel consumption.

Since the current transportation infrastructure does not include largenumbers of widely dispersed retail suppliers of natural gas forvehicles, it has been impractical to produce vehicles that are fueledsolely by gaseous fuels like natural gas due to range limitations.Instead, it is more practical to equip vehicles with a supply of both aliquid fuel, such as diesel fuel, and an auxiliary supply of gaseousfuel such as natural gas.

Accordingly, there is a continuing need for a system which is capable ofburning not only diesel fuel, but diesel fuel combined with natural gasso as to lessen the emissions of the diesel combustion engine. What isfurther needed is such a system that does so with as little retrofittingas possible to the existing fuel intake systems and configuration, inorder to lessen the complexity and the cost of the system and also toenable existing diesel engines to be retrofitted. What is also needed issuch a system that filters the blow-by gas of the diesel enginecrankcase, so as to maintain a clean and filtered lubricating oil withinthe crankcase, while lessening the environmental impact of blow-bygasses that are introduced into the combustion chamber. The presentinvention fulfills these needs, and provides other related advantages.

SUMMARY OF THE INVENTION

The present invention is directed to a multi-fuel engine system. Themulti-fuel engine system starts with a diesel engine having a dieseltank fluidly connected to a combustion chamber by a first supply line.The diesel engine may include a fuel injector rail and a fuel injectorthat extends into the combustion chamber, in which case the first supplyline is fluidly connected to the combustion chamber through the fuelinjector rail and fuel injector. The fuel injector is responsive to amicrocontroller as described below.

The engine preferably has a plurality of combustion chamberscorresponding to any number of a plurality of pistons in the engine.With a plurality of pistons and combustion chambers, the engine may alsoinclude a plurality of fuel injectors extending from the fuel injectorrail into each combustion chamber.

The system also has a natural gas tank fluidly connected to thecombustion chamber by a second supply line, which may also pass throughthe fuel injector rail and fuel injector if present. The natural gastank is preferably made from a puncture resistant material or carbonfiber. The natural gas tank and the second supply line are preferablypressurized.

The system also has a mixing chamber disposed in-line with the first andsecond supply lines, wherein the mixing chamber mixes diesel fuel fromthe diesel tank and natural gas from the natural gas tank to form amulti-fuel mixture before the combustion chamber. A microcontroller iscoupled to a sensor monitoring an operational characteristic of thediesel engine, particularly engine temperature, battery charge, engineRPMs, rate of acceleration, exhaust features, or PCV valve position.

The mixing chamber is responsive to the microcontroller for selectivelymodulating formation of the multi-fuel mixture. The mixing chamberpreferably processes the multi-fuel mixture by expanding, aerating,pressurizing, heating, or cooling, which is done is response to a signalfrom the microcontroller. The mixing chamber preferably mixes the dieselfuel and the natural gas in a range from pure diesel to a 1:1 ratio,also in response to a signal from the microcontroller.

The system preferably comprises a blow-by gas system comprising a PCVvalve disposed in-line with a recirculating line extending from acrankcase of the diesel engine to the mixing chamber. The blow-by gassystem further includes an oil filter in the recirculating line betweenthe crankcase and the PCV valve.

Other features and advantages of the present invention will becomeapparent from the following more detailed description, taken inconjunction with the accompanying drawings, which illustrate, by way ofexample, the principles of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings illustrate the invention. In such drawings:

FIG. 1 is a schematic illustration of vehicle with a multi-fuel systemof the present invention;

FIG. 2 is a schematic illustration of an engine incorporating amulti-fuel system of the present invention;

FIG. 3 is a schematic illustration of the fuel injector rail and fuelinjectors of the multi-fuel system of the present invention;

FIG. 4 is a schematic illustration of the multi-fuel system of thepresent invention;

FIG. 5 is a schematic illustration of a multi-fuel system of the presentinvention having a microcontroller operationally coupled to numeroussensors and a PCV valve;

FIG. 6 is a schematic illustration of the general functionality of themulti-fuel system of the present invention;

FIG. 7 is an elevational view of the blow-by filter, illustratingplacement of the intake, exhaust, and oil drainage ports;

FIG. 8 is an enlarged side view of the area indicated by circle 8 ofFIG. 7, illustrating the closed top portion of the canister of theblow-by filter;

FIG. 9 is an enlarged fragmented view taken from circle 9 of FIG. 7,illustrating the bottom portion of the canister of the blow-by filter;and

FIG. 10 is a cut-away side view of the blow-by filter, illustrating thefiltering assembly with its multiple layers of metal mesh of differinggauges.

DETAILED DESCRIPTION OF THE INVENTION

As shown in the accompanying drawings, for purposes of illustration, thepresent invention resides in a dual diesel and natural gas system for adiesel combustion engine. In accordance with an embodiment of thepresent invention, a diesel engine system is converted into a multiplefuel engine which operates on a combination of diesel fuel and naturalgas fuel. In a preferred embodiment, the multiple fuel system operateson diesel as a first fuel and natural gas as a second fuel, beingcombined with diesel to lessen emissions. The system of the presentinvention can also potentially cause a dramatic increase in engineefficiency, such that the user can keep his car fueled for much lessthan it would cost to fuel a standard diesel engine.

In accordance with the invention, existing diesel engines can beretrofitted with as little modification to the standard diesel engine aspossible. For example, the only additions required to the standarddiesel engine would be a tank for the natural gas and fuel line, amixing chamber for the mixing of the fuels, a microcontroller, and inone embodiment a PCV valve and a blow-by gas filter. Although calibratedfuel injectors may be used, these are not necessary, and no additionalalterations are needed for the actual engine.

With reference now to FIG. 1, the dual fuel system is generally referredto herein by the reference number 10. A vehicle 12 is shown with anengine 14, a fuel injector rail 24 and four fuel injectors 26. By andlarge, fuel injection systems have replaced the old carburetor systems.Carburetors supplied fuel to the engine based on suction, while fuelinjection systems supply fuel via a direct injection spray. The amountof fuel sprayed into the engine's combustion chamber may correspond tothe amount of air entering the engine, resulting in the fuel injectionsystem making the engine much more efficient.

Normally, a fuel injection system only functions with one type of fuel.The dual fuel system of the present invention functions with bothstandard diesel as well as natural gas fuels. The dual fuel system 10can be retrofitted into an existing vehicle, or it can be factoryinstalled into a new vehicle. The vehicle 12 illustrated in FIG. 1 isfor exemplary and illustration purposes only. It will be appreciatedthat the system 10 of the present invention can be used in a variety ofvehicles and in fact in conjunction with diesel engines which are notpart of a vehicle.

The system 10 of the present invention requires both the standard dieseltank 16 as well as a separate natural gas tank 18. The natural gas tank18 may be made of carbon fiber or some other material that is punctureresistant and capable of transporting materials under pressure.Typically, the vehicle is retrofit, such that the natural gas tank 18 ismounted within a sufficiently large space of the vehicle, theundercarriage of the vehicle 12, or any other place where the tank 18will fit without compromising the safety and functionality of thevehicle 12.

With reference now to FIG. 2, a partial cross-sectional and diagrammaticview of a typical engine is shown. Air is received through the intakemanifold 30 into the combustion chamber 38 as the intake cam shaft 42 isdrawn up. This creates the vacuum necessary to draw the air in. When theintake cam shaft 42 is pushed down, fuel is injected into the combustionchamber 38 by the fuel injector 26. The fuel injector 26 basically actsas an atomizer, producing a fine spray of fuel that is easily ignited bya glow plug 40 as the piston 32 is raised by the crankshaft 36,compressing the fuel to a point of ignition. The resulting combustionforces the piston 32 down into the crankcase 34, which in turn rotatesthe crankshaft 36. At this point, the exhaust camshaft 44 draws back tocreate the vacuum necessary to drive the exhaust out of the combustionchamber 38 through the exhaust manifold 46.

The fuel injector 26 is supplied by the fuel supply line 50 from theexpansion and mixing chamber 20, which is supplied the diesel fuel 52from tank 16 and/or the natural gas 54 from tank 18. Typically, theengine will run on either diesel fuel from supply line 52 alone, or acombination of diesel fuel from line 52 and natural gas from line 54.

Hoses or fuel supply lines 28 interconnect the diesel and natural gastank 16 and 18 with a mixing and expansion chamber 20. With referencenow to FIG. 3, the diesel fuel supply from tank 16 is illustrated withits supply line 52 to mixing and expansion chamber 20. Similarly, thenatural gas supply tank 18 is shown with supply line 54 to the mixingand expansion chamber 20. At the expansion and mixing chamber 20, thefuels are aerated and conditioned as necessary for proper mixing anduse. The ratio of each fuel supplied can vary depending upon engineparameters. The fuel may be heated or cooled in the mixing chamber 20.The mixed and conditioned fuel is then sent via line 50 either directlyto the engine, such as the illustrated fuel injector rail 24 havingapertures 56 which lead to the fuel injectors 26 themselves. Amicrocontroller or ECU 58 is used to control the input of the fuelthrough the fuel injectors 26 into the cylinders of the engine. Theelectronic control unit (ECU) 58 tells the fuel injectors 26 when toinject fuel and how much fuel to inject. The ECU 58 is typically part ofthe vehicle's computer control system. It is also contemplated by thepresent invention that the mixed fuel be delivered to the intakemanifold 30 where it will be mixed with a portion of air forintroduction into the cylinder and combustion chamber 38.

With reference now to FIG. 4, a schematic drawing of the system of thepresent invention is shown. The supplies of diesel fuel 16 and naturalgas fuel 18 are fed into the expansion and mixing chamber 20. Amicrocontroller 60, with sensor inputs, is used to determine theproportion of diesel fuel to natural gas fuel at any given time. Theconditioning of the mixed fuel, such as by aerating, pressurizing,heating or cooling, etc. is also controlled by the microcontroller 60.The microcontroller 60 may be a separate microcontroller from the ECU58, but may also comprise the ECU 58 or a modified ECU 58.

With reference now to FIG. 5, the controller 58 and/or 60 has sensorinputs to make these determinations. Sensors may include enginetemperature sensor 62, battery sensor 64, a PCV valve sensor 66, anengine RPM sensor 68, an accelerometer sensor 70, and an exhaust sensor72. Other sensors that are typically found in the vehicle and whichprovide data and signals to the ECU 58 may also be used. In fact, thedata from the sensors may be fed directly to the microcontroller 60, orto the ECU 58, which then supplies the data to the microcontroller 60.

With reference again to FIG. 3, it will be appreciated that the presentinvention contemplates the use of a unique fuel injector rail 24 whichis designed to supply the combined and mixed diesel and natural gas fuelto the combustion chambers of the cylinders of the engine. In such case,it is still contemplated that a single fuel injector 26 will be used ineach combustion chamber of each cylinder of the engine so as to supplythe already premixed fuel supply. It is also contemplated by the presentinvention that the existing fuel intake and injecting system of theengine be used so as to modify the engine as little as possible tominimize the complexity and expense of retrofitting the vehicle orengine.

With reference to FIGS. 4 and 5, in a particularly preferred embodimenta PCV valve 74, which is controlled by microcontroller 60, regulates theflow of blow-by gasses drawn from the engine crankcase 34 and suppliedto the engine for burning. This may be done, for example, by regulatingthe engine vacuum in a combustion engine through a digital control ofthe PCV valve 74. The data obtained from the sensors 62-72 by thecontroller 58 and/or 60 may be used to regulate the PCV valve 74 as wellas an oil filter 76.

As illustrated in FIG. 4, a filter 76 is used to filter the blow-bygasses, thus returning filtered oil back into the crankcase 34 of theengine 14, while supplying filtered, pure blow-by gas through the PCVvalve 74 to be burned in the engine 14, such as by introducing thefiltered blow-by gas into the expansion chamber 20 to be combined withthe diesel and/or natural gas fuels.

The oil filter 76 illustrated in the figures herein is typically inaddition to the regular oil filter, wherein the oil itself is filteredto remove contaminants. Instead, this filter 76 is for the filtering ofoil from the blow-by gas removed from the crankcase. The typicallycylindrical filters 76 can be clamped in place or threaded into place asneeded. Off-the-shelf after market separators or oil filters or theuniquely designed filter 76 illustrated and described herein can beused. While impurities from the oil may be removed, such that the oilreturned to the crankcase is filtered and will have better efficacy andlife, it is the removal of the liquid oil from the blow-by gas which isof particular interest and concern in the present invention in order notto introduce the oil or contaminants into the combustion chamber, whichwould result in increased emissions instead of decreased emissions.

With reference now to FIG. 6, a schematic view of an engine 14 and theoperation of the blow-by filter 76 in conjunction with a PCV valve 74are shown. As illustrated, the blow-by filter 76 and the PCV valve 74are disposed in-line in a recirculating line 75 between the crankcase 34of the engine 14 and the intake manifold 30 and fuel line 50 of theengine 14. In a diesel engine, the intake manifold 30 receives a mixtureof fuel and air via fuel line 50 and air line 78. Fuel line 50 alsoprovides fuel for direct injection into the combustion chamber 38. In agasoline engine, the fuel line 50 does not directly inject fuel into thecombustion chamber 38, rather, the fuel line 50 is only connected to theintake manifold 30. An air filter 80 receives fresh air 82, which isdelivered through the intake manifold 30 to a piston cylinder andcombustion chamber 38 as the piston 32 descends downwardly within thecylinder 84 from the top dead center. As the piston 32 descends downwardwithin the cylinder 84, a vacuum is created within the combustionchamber 38. Accordingly, an input camshaft 42, rotating at a speed timedwith the crankshaft 36 is designed to open an input valve 88 therebysubjecting the intake manifold 30 to the engine vacuum. Thus, air isdrawn into the combustion chamber 38 from the intake manifold 30.

Once the piston 32 is at the bottom of the piston cylinder, the vacuumeffect ends and air is no longer drawn into the combustion chamber 38from the intake manifold 30. At this point, the piston 32 begins to moveback up the piston cylinder 84, and the air in the combustion chamber 38becomes compressed. In a diesel engine, fuel is injected directly intothe combustion chamber 38 from the fuel line 50. This injection may befurther aided by more compressed air from a compressed air line 90. Thecompressed air line 90 is not present in a gasoline engine. As the airand fuel in the combustion chamber 38 is compressed, it heats up untilthe fuel ignites and combustion occurs.

The rapid expansion of the ignited fuel/air in the combustion chamber 38causes the piston 36 to move downwardly within the cylinder 84. Aftercombustion, an exhaust camshaft 44 opens an exhaust valve 92 to allowescape of the combustion gasses from the combustion chamber 38 out anexhaust manifold 46.

Typically, during the combustion cycle, excess exhaust gasses slip by apair of piston rings 94 mounted in the head 96 of the piston 32. These“blow-by gasses” enter the crankcase 34 as high pressure and temperaturegasses. Over time, harmful exhaust gasses such as hydrocarbons, carbonmonoxide, nitrous oxide and carbon dioxide can condense out from agaseous state and coat the interior of the crankcase 34 and mix with theoil 95 that lubricates the mechanics within the crankcase 34. Asdiscussed above, the PCV valve 74 is designed to recycle these blow-bygasses from the crankcase 34 to be re-burned by the engine 14. This isaccomplished by using a pressure differential between the crankcase 34and the intake manifold 30. This process may be digitally regulated by amicro-controller.

PCV valve 74 includes a one-way check valve (not shown) that opens toallow blow-by gasses through the valve 74 when the vacuum between theintake manifold 30 and the crankcase 34 is strong enough. With the checkvalve open, blow-by gasses pass through the PCV valve 74 to be recycledthrough the intake manifold 30. The check valve can also be controlledby a microcontroller for added fuel efficiency.

Blow-by gasses are not pure fuel vapors. Rather, when the un-ignitedfuel is pulled into the crankcase 34, past the piston rings 94, the fuelvapors mix with the oil 95 that lubricates the mechanics within thecrankcase 34. Over time, harmful exhaust gasses such as hydrocarbons,carbon monoxide, nitrous oxide and carbon dioxide can condense out froma gaseous state to mix with the oil 95 and the fuel vapors. Thus, theresulting blow-by gasses contain harmful impurities making themunsuitable for re-burning in the engine. In a diesel engine, diesel fuelcontains more oil than gasoline, so the blow-by gasses are significantlyoilier. Oily and sludgy blow-by gasses are not only non-suitable forre-burn, they also tend to gum up the PCV valve 74 making it impossiblefor the blow-by gasses to be recycled at all.

Thus, the present invention incorporates a filter 76 to clean theimpurities out of the blow-by gasses before they enter the PCV valve 74.The blow-by filter 76 also returns filtered engine oil 95 back into thecrankcase 34 by return line 77 for further use. In one embodiment, acheck valve is used in the return of the oil back into the crank case.This prevents untreated oil from entering into the oil drainage port ofthe filter 76. Sensors may be used to detect if the filter 76 becomestoo full, and a purging system may be used to resort back to the OEM. Awarning system, including alarms, LED lights, etc. may be used to notifythe operator of such a situation.

The blow-by filter 76 is particularly illustrated in FIGS. 7-10. In FIG.7, the blow-by filter 76 is shown in a side view. The blow-by filter 76includes a canister 98 with a closed top portion or lid 100 and a bottomportion 102. The canister 98 may be made of metal, plastic, or any othermaterial or composite that is suitable for use in high temperature, highpressure tasks. The closed top portion 100 of the canister 98 includes ablow-by intake port 104 and a fuel vapor exhaust port 106. The blow-byintake port 104 receives the blow-by gasses into the interior of thecanister 98. The fuel vapor exhaust port 106 vents purified blow-bygasses from the interior of the canister 98 to the PCV valve 74, asillustrated in FIG. 6.

As illustrated in FIG. 7, the closed top portion 100 of the canister 98is typically not removable from the canister 98. However, the bottomportion 102 of the canister 98 includes a removable cover 108 withclamps 110. The removable cover 108 includes an oil drainage port 112that allows the purified oil 95 to drain back into the crankcase 34 ofthe engine 14. FIGS. 8 and 9 are enlarged views of areas “8” and “9” ofFIG. 7, illustrating the upper portion 100 and lower portion 102 of theoil filter canister 98. With reference to FIG. 9, the oil drainage port112 may be offset from the center of the removable cover 108 in order toaccount for the angle of the blow-by filter 76 as it is mounted inrelation to the vehicle 12. The removable cover 108 allows for easyaccess to the interior of the canister 98, making for easy cleaning andreplacement of the contents of the canister 98.

With reference now to FIG. 10, the blow-by filter 76 is shown in acut-away side view. Here, the filtering assembly 114 is shown in detail.The filtering assembly 114 comprises multiple layers of metal mesh 86 ofdiffering gauges. These layers of metal mesh 86 are loaded into thecanister 98 through the canister's open end, after removing the cover108. The layers of metal mesh 86 may be of the same type of metal, ormay be of different types of metal. The types of metal that may be usedinclude, but are not limited to, steel, stainless steel, aluminum,copper, brass, bronze, etc.

In operation, unfiltered blow-by gasses are received by the blow-byintake port 104 in the closed top portion 100 of the canister 98. Theblow-by gasses begin to circulate through the layers of metal mesh 86 inthe canister 98. Different contaminants and impurities are trapped ateach layer of metal mesh 86 depending on the gauge of the mesh and typeof the metal. Larger contaminants are filtered by larger gauges of metalmesh 86. Smaller contaminants and impurities are filtered by the finergauges of metal mesh 86. Likewise, some impurities may be trapped bycertain types of metal. As the blow-by gasses work through the filteringassembly 114, contaminants and impurities are trapped leaving two mainbyproducts, namely, cleansed engine oil 95 and purified fuel vapor. Thecleansed engine oil 95 eventually collects in the bottom portion 102 ofthe canister 98, where it drains via the oil drainage port 112 back tothe crankcase 34 of the engine 14. The purified fuel vapor is ventedthrough the fuel vapor exhaust port 106 in the closed top portion 100 ofthe canister 98 to pass to the PCV valve 74 to be recycled through theintake manifold 30 or added to the diesel and/or natural gas fuelmixture in the expansion chamber before being introduced into thecombustion chamber 38 of the engine 14.

When the filtering assembly 114 requires periodic cleaning andmaintenance, it can be easily removed from the canister 98 by unlatchingthe clamps 110 and removing the lid 108 from the bottom portion of thecanister 98. It will be appreciated that the blow-by oil filter 76 mayinclude sealing gaskets and the like as necessary to create a sealbetween the canister 98 and the removable lid 108, so as to prevent oiland other contaminants from leaking out. The present inventioncontemplates that priming might be involved when changing the oilseparator/filter elements of the filtering assembly 114.

The computerized controller 60 can be used to monitor the filteringprocess of the blow-by gasses and the PCV valve 74 and so as to controlwhether and to what degree the purified blow-by gasses pass through thePCV valve 74 and into either the fuel line 50, the expansion and mixingchamber 20 or directly into the air intake manifold 30 or air line 78.In any event, the blow-by gas which has been filtered presents a muchcleaner gas which produces less undesirable emissions.

Although several embodiments have been described in detail for purposesof illustration, various modifications may be made without departingfrom the scope and spirit of the invention. Accordingly, the inventionis not to be limited, except as by the appended claims.

What is claimed is:
 1. A multi-fuel engine system, comprising: a dieselengine having a diesel tank fluidly connected to a combustion chamber bya first supply line; a natural gas tank fluidly connected to thecombustion chamber by a second supply line; a mixing chamber disposedin-line with the first and second supply lines, wherein the mixingchamber mixes diesel fuel from the diesel tank and natural gas from thenatural gas tank to form a multi-fuel mixture before the combustionchamber; and a microcontroller coupled to a sensor monitoring anoperational characteristic of the diesel engine, wherein the mixingchamber is responsive to the microcontroller for selectively modulatingformation of the multi-fuel mixture.
 2. The multi-fuel engine system ofclaim 1, wherein the mixing chamber processes the multi-fuel mixture byexpanding, aerating, pressurizing, heating, and/or cooling.
 3. Themulti-fuel engine system of claim 2, wherein the mixing chamber isresponsive to the microcontroller for processing the multi-fuel mixture.4. The multi-fuel engine system of claim 1, wherein the mixing chambermixes the diesel fuel and the natural gas in a range from pure diesel toa 1:1 ratio, in response to a signal from the microcontroller.
 5. Themulti-fuel engine system of claim 1, wherein the natural gas tankcomprises a puncture resistant material or carbon fiber.
 6. Themulti-fuel engine system of claim 1, wherein the natural gas tank andthe second supply line are pressurized.
 7. The multi-fuel engine systemof claim 1, wherein the operational characteristic monitored by thesensor comprises engine temperature, battery charge, engine RPMs, rateof acceleration, exhaust features, and/or PCV valve position.
 8. Themulti-fuel engine system of any of claims 1-7, further comprising ablow-by gas system including a PCV valve disposed in-line with arecirculating line extending from a crankcase of the diesel engine tothe mixing chamber.
 9. The multi-fuel engine system of claim 8, whereinthe recirculating line of the blow-by gas system further comprises anoil filter between the crankcase and the PCV valve.
 10. The multi-fuelengine system of any of claims 1-7, further comprising a fuel injectorrail on the diesel engine and a fuel injector extending from the fuelinjector rail to the combustion chamber, wherein the fuel injector isresponsive to the microcontroller.
 11. A multi-fuel engine system,comprising: a diesel engine having a diesel tank fluidly connected to acombustion chamber by a first supply line; a natural gas tank fluidlyconnected to the combustion chamber by a second supply line; a mixingchamber disposed in-line with the first and second supply lines, whereinthe mixing chamber mixes diesel fuel from the diesel tank and naturalgas from the natural gas tank to form a multi-fuel mixture before thecombustion chamber, wherein the diesel fuel and the natural gas aremixed in a range from pure diesel to a 1:1 ratio, and wherein the mixingchamber processes the multi-fuel mixture by expanding, aerating,pressurizing, heating, and/or cooling; and a microcontroller coupled toa sensor monitoring an operational characteristic of the diesel engine,wherein the mixing chamber is responsive to the microcontroller forselectively modulating mixture of the diesel fuel and the natural gas toform the multi-fuel mixture, and wherein the mixing chamber isresponsive to the microcontroller for processing the multi-fuel mixture.12. The multi-fuel engine system of claim 11, wherein the natural gastank comprises a puncture resistant material or carbon fiber.
 13. Themulti-fuel engine system of claim 11, wherein the natural gas tank andthe second supply line are pressurized.
 14. The multi-fuel engine systemof claim 11, wherein the operational characteristic monitored by thesensor comprises engine temperature, battery charge, engine RPMs, rateof acceleration, exhaust features, and/or PCV valve position.
 15. Themulti-fuel engine system of any of claims 11-14, further comprising ablow-by gas system comprising a PCV valve disposed in-line with arecirculating line extending from a crankcase of the diesel engine tothe mixing chamber.
 16. The multi-fuel engine system of claim 15,wherein the recirculating line of the blow-by gas system furthercomprises an oil filter between the crankcase and the PCV valve.
 17. Themulti-fuel engine system of any of claims 11-14, further comprising afuel injector rail on the diesel engine and a fuel injector extendingfrom the fuel injector rail to the combustion chamber, wherein the fuelinjector is responsive to the microcontroller.
 18. A multi-fuel enginesystem, comprising: a diesel engine having a fuel injector rail, a fuelinjector extending from the fuel injector rail into a combustionchamber, and a diesel tank fluidly connected to the combustion chamberby a first supply line through the fuel injector rail and fuel injector;a natural gas tank fluidly connected to the combustion chamber by asecond supply line; a mixing chamber disposed in-line with the first andsecond supply lines, wherein the mixing chamber mixes diesel fuel fromthe diesel tank and natural gas from the natural gas tank to form amulti-fuel mixture before the combustion chamber; a microcontrollercoupled to a sensor monitoring an operational characteristic of thediesel engine, wherein the mixing chamber is responsive to themicrocontroller for selectively modulating formation of the multi-fuelmixture, and the fuel injector is responsive to the microcontroller foradding the multi-fuel mixture to the combustion chamber; and a blow-bygas system comprising an oil filter and a PCV valve disposed in-linewith a recirculating line extending from a crankcase of the dieselengine to the mixing chamber.
 19. The multi-fuel engine system of claim18, wherein the mixing chamber is responsive to the microcontroller forprocessing the multi-fuel mixture by expanding, aerating, pressurizing,heating, and/or cooling.
 20. The multi-fuel engine system of claim 18,wherein the mixing chamber mixes the diesel fuel and the natural gas ina range from pure diesel to a 1:1 ratio, in response to a signal fromthe microcontroller.
 21. The multi-fuel engine system of claim 18,wherein the natural gas tank comprises a puncture resistant material orcarbon fiber, and the natural gas tank and the second supply line arepressurized.
 22. The multi-fuel engine system of claim 18, wherein theoperational characteristic monitored by the sensor comprises enginetemperature, battery charge, engine RPMs, rate of acceleration, exhaustfeatures, and/or PCV valve position.